Scratch that, just got the game and played for a little over an hour, felt like how it did on the PS1 so that's a good thing for me, enjoying it quite a lot. Only gripe I have is the Wumpa Coins, can't understand how the rate of coins differ, it says in-game, coins you get depends on your position? But I've been first quite a lot and only got 40 coins 2 times while most of the time I get 20 coins, and also I don't like the always online thing especially that it's a grind for the Pit Stop unlocks.
Not so sure about this one on the boss, I've played for a little over an hour and only beaten Ripper Roo, and I've noticed he's almost always near me and only lost by 1 second, while on group race(Adventure mode) I've beaten them by around 5-6 seconds, given I've been hit a couple of times while boosting like crazy too(on both occasion).
Yeah the bosses work differently to regular ai. They seem to have some form of catchup.
PS4 Pro, Nintendo Switch, PC: i5-4670k, RX470.